Electrical connectors



1957 e. SCHERTEL' ETAL 6 ELECTRICAL CONNECTORS Filed July 14, 1955Fig.1. Fig.2.

INVENTORS Gunther Schenel and Fr iedrich Schmidt ATTORNEY United StatesPatent ELECTRICAL CONNECTORS Giinther Schertel and Friedrich Schmidt,Nurnherg, Germany, assignors to Siemens-SchuckertwerkeAktiengesellschaft, Erlangen, Germany, a corporation of GermanyApplication July 14, 1955, Serial No. 522,119 Claims priority,application Germany August 21, 1954 3 Claims. (Cl. 339-272) Ourinvention relates, generally, to electrical connectors and, moreparticularly, to connectors for making terminal connections to electricmeters and the like.

Electrical connectors of the socket type having undulated sides toobtain an.elastic grip on conductors, particularly aluminum conductors,are known in the prior art. In connectors previously known abroad, thebody or socket of each connector was made of sheet steel and wasundulated along the whole length of each side surface to obtain thedesired elasticity.

The foregoing connectors had the disadvantage that their operation wasweak or soft, that is, the terminal screw had to be screwed in asubstantial distance before the desired grip-pressure was obtained. Onthe other hand, when the characteristics of the connector are such thatits operation is too hard, the danger arises that the connectors ofcorrespondingly greater thickness will break during the manufacturingprocess, particularly when undulating, or when fastening the terminalscrew.

An object of our invention is to overcome the aforesaid disadvantages ofprior electrical connectors.

A more specific object of our invention is to provide a connector havingsufiicient elasticity to secure good electrical contact, even when analuminum conductor is utilized.

Another object of our invention is to provide a connector which requiresa relatively small amount of turning of the terminal screw to obtain asatisfactory grippressure.

Other objects of our invention will be explained fully hereinafter orwill be apparent to those skilled in the art.

In accordance with our invention, the undulations of the side surfacesof the body or socket of a connector extend only over a part of saidsurfaces. The socket is made from a material, such as brass, which willdeform over its yield point and obtain its elastic properties only afterundulation, thereby preventing the breaking of the socket during themanufacturing process or operation of the connector.

For a better understanding of the nature and objects of the invention,reference may be had to the following detailed description, taken inconjunction with the accompanying drawing, in which:

Figures 1 and 2 are views, in end elevation, of two connectors embodyingthe principal features of the present invention.

As shown in Figs. 1 and 2 of the drawing, the undulation 5 extends onlyover a distance a, which is approximately the same as the smallestdiameter b of the socket 1, that is, the diameter of the terminal screw3. It is advisable to make the socket 1 of a material other ice thansteel, such as brass, which will deform over its yield point and obtainits elastic properties only after undulation. Such a terminal connectorhas an operating characteristic which is rather hard, that is, only asmall amount of turning of the terminal screw 3 is necessary to obtain asatisfactory grip-pressure. However, the connector also has thenecessary elasticity to secure a good contact pressure, even in casealuminum conductors are utilized. The utilization of a soft material,such as brass, which obtains its elastic properties only after theundulation will prevent the breaking of the socket during themanufacturing process or operation of the connector.

A contact pressure of 500 kg. (1100 lbs.) per screw at only, forinstance, 0.3 mm. (0.012") tensioning-dis tance is obtained with saidterminals. At said tensioning-distance of only /3 mm. (0.012) an energyaccumulation of /z mkg. (0.72 ft. lb.) is obtained.

When the socket is made of brass, the thickness of the socket walls isgreater than when the socket is made of steel. Generally, the sides ofthe socket are made 1 mm. (0.039") thick, so that the terminalconnectors are made nearly as narrow as the conventional steelconstructions, which, because of the undulation extending along thewhole length of the socket, have considerable Width so long as theconductor is not inserted into the socket and the terminal screwtightened.

A particularly advantageous modification of the terminal connector isshown in Fig. 2. As shown, the undulation 5 of the socket l is utilizedto secure the threaded insert 2 in its position as well as to providethe desired elasticity to take care of expansion and contraction of theconductors held by the connector.

Since numerous changes may be made in the above described constructionand diflerent embodiments of the invention may be made without departingfrom the spirit and scope thereof, it is intended that all mattercontained in the foregoing description or shown in the accompanyingdrawing shall be interpreted as illustrative and not in a limitingsense.

We claim as our invention:

1. A terminal connector having an integral socket of a generallyrectangular cross section, a terminal screw extending through one end ofthe socket, two opposite sides of the socket having a single undulationin each side, and the undulation in each side extending only over a partof the surface of said side.

2. A terminal connector having a socket of a generally rectangular crosssection, a terminal screw extending through one end of the socket, twoopposite sides of the socket having a single undulation in each side,the undulation in each side extending only over a distance correspondingto the diameter of the terminal screw, and said socket being composed ofa material, such as brass, which obtains its elastic properties onlyafter being undulated.

3. A terminal connector as claimed in claim 2, characterized by anenergy-accumulation capacity of approximately ,5 mkg. (0.72 ft. lb.) perscrew at a deformation distance of approximately /3 mm. (0.012").

References Cited in the file of this patent UNITED STATES PATENTS1,741,804 Zilliox Dec. 31, 1929 FOREIGN PATENTS 733,024 Germany Mar. 17,1943

